Evolution of the Colors of North American Land Birds

Front Cover
California Academy of Sciences, 1893 - Animals - 361 pages
0 Reviews
 

What people are saying - Write a review

We haven't found any reviews in the usual places.

Selected pages

Other editions - View all

Common terms and phrases

Popular passages

Page 5 - 7. That gemmules are thrown off by all physiological cells, not only during the adult state of the organism, but during all stages of development. Or, in other words, that the production of these cell-seeds depends upon the adult condition of parent cells; not upon that of the multicellular organism.
Page 106 - Next, it must be clearly understood that the life which it is the object, so to speak, of natural selection to preserve, is primarily the life of the species; not that of the individual. Natural selection preserves the life of the individual only in so far as this is conducive to that of
Page 93 - Although we know very little about the psychology of the lower animals, we do observe in many cases that small details of mental organization are often wonderfully constant and uniform throughout all members of a species, even where it is impossible to suggest any utility as a cause." In commenting on the display of ornaments by male birds, Mr. Wallace writes:
Page 35 - lives in brackish water, while A. milhausenii inhabits water which is much salter. They have always been regarded as distinct species, differing in the form of the tail lobes and the character of the spines they bear. And yet, by gradually altering the
Page 27 - were not written by Homer, but by another man of the same name who lived at the same time.
Page 65 - the influence of the originative or conscious force in evolution, that it is a distinct species in the category of forces. Assuming it to be such, I have given it the name of Bathmism." Bathmism, then, is the vital force inducing growth. Prof. Cope has stated as a fundamental law of
Page 126 - Selection, which is due to the exposure of the organism to a different environment, is often produced by the organism's entering a new environment without there being any change in either the new or the old environment. Fourth, that when Passive Natural Selectionis produced by change in the environment,
Page 199 - Several years ago, in May, I saw one of these birds occupying an exposed perch on a pear tree in bloom, about which many bees were darting. Several times I observed that the bird caught the insects without leaving his perch by quickly turning his head
Page 65 - the animal functions are known to be physical and chemical, and if there be any one which appears to be less explicable by reference to these forces than others, it is that of nutrition. Probably in this instance force has been so metamorphosed
Page 105 - usually less extensive, and always of a lower taxonomic rank, has done more than any other single thing to advance the science of Zoology; for the whole theory of evolution turns, as it were, upon this point.

Bibliographic information